Fluid-pressure system for presses



July 6, 15926.

J. F. MADDEN FLUID PRESSURE SYSTEM'FOR PRESSES Filed August 27, 1924 3j INVENTOR ATTORNEYS Patented YJuly 6,

,FJAMES PATRICK MADnEN, .or

BETHLEHEMJ VPEVNNSYIJYANI, SISGNoR' T0 :i BESH'LE- nEMsTEELjcoMPaNY. l Y y ""rL'Uin-rnnsstrnii SYSTEM',roa'rnnssnsg,

Myiiivention relates .to a method for con;-

' age losses `in a hydraulic vsystem andv is Lparticularly applicable to" hydraulic presses in 'which -a sustained pressurev is required lto 'be Aapplied to aheated body. during the cooling' andthe corresponding contraction thereof.`

In the manufacture, for example, of artiicial resins and bone substitutes by the Acon-V den'sation'ofaldehydes and lphenols, the con-y vfdensation product is submitted to alprede- Atermiiied 4degree of initial pressure. After.

,saidinitial pressure "has been Vappliedthe fproducti's heated bysteam or other convenient means' and a's'ubstantially higher pressureis applied. to the heated product forthe desired period of time. Y Duringthe subse-V quent cooling of the mas'sthis higherpresi suie'sliould be evenly maintained, but owing to 'thecontraction ofthe mass in cooling, it

is dilicult' to fully maintain the desired pressure.' VThis condition is aggravated by the leakage losses. iiievitableiinl a hydraulic sysi tem.,v Furthermore, ywhen a, number of'suchv presses are in use, their independent operation from a common -main'causes local luctuations in pressure that are undesirable in a Y process of this nature.

The objects of my invention are, therefore, to, overcome the effect-s of these fluctuations,` to provide compensation for-,leakage losses and to insure a sustainedpressure in the press', regardless ofthe contraction or deformation of the material under treatment. I attain these objects by interposing a vsmall secondary or auxiliary accumulator between the hydraulic main and the press, said accumulator being'of suilicient capacity to como the ram in .the press due tothe contraction or the deformation of thefproduct, and

also to compensate Jfor such pressure leakageas might reasonably occur. Y h Y yApparatus made in accordance with my invention is illustrated in the accompanying drawings, forming a part of this application, in which f Fig.V 1 is a view in elevation of a'hydraulicj In'Fi'gs. 1 and 2, Ishow al hydraulic press 1l of the multiple hotplatetypehaving series of plates 12 wthsteam connections 13` Ap'piiatien fiiezinugust 27, 1924. seriai No. 734,410.12 i' i A f. equally spaced betweenthe head oi'jtliepress trolling the pressure reduction due to leak-A 14: and the ram 1'5, said ramoperatingfin the valve Q26.` Y The hydraulic mains-21 and 23 are intended for an .initial or lowpressure and'fa'.higherpressure,respectively. *l

'Ilalsof show an auxiliary'[accumulator'31 of they usual' type having a ram 32, a cylinv der 33, an inlet 34 and counterweights 37.

T he inlety 34 of the accumulator isv connected i 1o the high pressure main 23through'the i valve l35, being also cross connected with the pressl 11 through the valve 36.

In operation the material to loaded between the platesl2 ofthe press and a low pressurei's admitted from the'lmain 21 through the openV valvefl22,valves2&1,` 26, 35 and `36 Vbeing closed'. A'fterithis initial presbe treated n.

sure:has'.beensufliciently applied, steam is Y v circulated inthe platesf12 through thev steam. o v yconnections513and lthe materialisfthereby heated@ f During the heating process a' high'- er pressure is-admitted Vto the'cyli'nder from the vhigh pressure main'v 23 by Vclosing thev valve 22and opening the valve 24E, valves 26,

35 and 36 remaining closed. VVhenthemax imuin desired pressure has beenattained high pressure main iscut'o by closing the valve 24 and this high pressure is admitted vto the auxiliary .accumulator 31 by opening 'the valve 35, valves22, 26 and 36 remaining closed. yAs soon asl the accumulatorvvhas illed n to its capacity, the valve 35 is closed and the pensatefforthe predetermined displacement accumulator is placed 'in communication with the pressl by opening the valve 36, being kept in' AcommunicationY during `the heating and :cooling periods of the 'l treatment.l ,'Duringf this time therewith y ycommunication betweenvthe press and the f the vvalves 22,24, 26 vand 35 arekept closed thereby entirely isolating ythe Vpress 11V and` the auxiliary accumulator 31 from' the pres-i sure 'system-` vThe contraction of the heated materiallduring 'its cooling period is attended by a correspondingupward displacement of the press ram 1.5..v "Owing to the reserve. y of Lpressure vin the auxiliary accumulatorl31 said upward displacemento-the press ram 15 does not -involve a loss of pressurein the press cylinder 16. Likewise any 'pressure f leakage past thepacking `ottlie'press rain is compensatedbythe reserve of pressure in v"the auxiliary accumulator.

v is opened to relase the"pressure{imposed'n4 Gn completion of the Vcooling period, the valve lo Visciosed and.tlieeexliaustV valve 26 on the material undert'reatment and effect the downward travel of theY press ram.V

,y'l'lliile liavedescribedaspecific application vo'my invention', it will be evident to anyonev skilled iii the art that this invention y is Widely applicabletoaiiy `fluid pressure leakage losses or for' local reductionsin pres v. sure, so as to'ei'iiect the'siistained application of a predetermined pressure. lt is also evident that While I have herein Vdescribed an application of my invention to a'single liy-V svstenigivliere compensation is required for draulic press, it is susceptiblepof application to a series of such presses soasto eti'e'ct their independent operatioii.A l, therefore, vdo not limitmyinvention to vthe specific purpose I have Aindicated nor'to the specific combina- Vtion Vo'is elements I have described; 4 Y I Having thus described the invention what l claimas neu7 anddesire tor-secure byLettersf Patent is :e Y y v l. The combination, With fluid 'pressure operated mechanism, of aii auxiliary accumulator, means for `supplying fluid under pressure to'said mechanism and to the accu- I mnlator,V and means for connectingtlieacycuinulator Withsaid mechanism. g

2. Y The combination, with fluid pressure operated'meclianism, oifan auxiliary accu- Qinulator, first conduit means for supplying,` fluidunderf pressure to said mechanisima valve in the conduit means, second conduit means connecting the first conduit means With the accumulator, avalve inthe second VconduitV means, third conduit means forl establishing con'iinunication of theY accumulator With'said meclianisin,and a valve in the third conduit means.

3. In combination With a, iiuid Vpressur "system includinga press, an auxiliary accumulator connected to the press, to com` Ypensate for pressure reduction iii the latter, and meansv to selectively connectV the accumulator to tliepress When'tlie latter is isolated from the system..

auxiliary accumulator having a capacity in excess of the Vdisplacement voit the press due to such a'coi'itraction, means to eectth'efin-V depeiident entry of fluid under pressure, toV` rthe press faiidtof the auxiliary accumulator,

meansl to cross connect the latter ivith the ln combination. ivith -a-'iu'id pressure system, a press for eii'ectin'g-an accurately 'sustained pressure on a lheated material dufr- Ying the vcooling,` and contraction thereo, an

press and means to isolate both tliepress and Y the auxiliary accun'iulator Vfrom the `fluid pressuresystem. d j i v 5. The combination `with a fluidpressur'e main, of :operated mechanism,connected to the main, an accumulator connected tothekv signature this 21st V,day of August-,1924;

JAMES 

